The present invention concerns sound absorbent structures for placement within a room to improve room acoustics by reducing audible low frequency sound waves.
In present use are devices, termed by the public sound traps, for enhancing room acoustics. Examples of such devices are disclosed in U.S. Pat. Nos. 2,502,020; 2,706,530; 2,160,638; 4,319,661 and 4,548,292 the latter issued to the present inventor. The general purpose of such sound absorbing articles is the reduction in low audible frequencies as at 250 HZ and below which degrade the acoustics of a room.
U.S. Pat. No. 4,319,661 discloses a pair of Helmholtz resonators disposed within a cylindrical housing filled with a mass of sound absorbent material. The resonators have outwardly orientated end surfaces each defining an opening proximate the end of the sound absorber unit. Wave access to the Helmholtz resonators is by way of acoustically porous end caps of the device.